An OLED display involves a flat panel display technology with great prospect. It has characteristics of self-illumination, simple structure, ultra-lightweight, fast response, wide viewing angle, low power consumption, flexible display and so on. Currently, the OLED display is favored by major display manufacturers and becomes a third-generation display following CRT (Cathode Ray Tube) display and LCD (Liquid Crystal Display).
Since the organic light emitting material used in the OLED panel is very sensitive to water and oxygen, the requirements for blocking water and oxygen are extremely strict. In general, a flexible film layer will be packaged on the organic light emitting material. The commonly used packaging structure is an inorganic or organic film layer. The inorganic film layer is usually dense, and its water-oxygen proof performance is good. However, during the deposition process, the stress of the film layer exists, which makes the inorganic film layer have poor bending properties and is prone to cracking and peeling. The fractured cracks are easily diffused in the inorganic film layer. The water-oxygen proof performance of the organic film layer is weak. However, it can effectively release the stress and avoid a further crack extension risk of the inorganic film layer. Therefore, at present, the OLED panel adopts a structure in which an inorganic film layer and an organic film layer overlap each other. The high water-oxygen proof capability of the inorganic film layer and the stress release of the organic film layer are complementary, and can be used to better meet the service life of the OLED panel.
The inventor of the present disclosure discovered in a long-term study that the current OLED panel uses a packaging structure of inorganic film layer-organic film layer-inorganic film layer, which has poor performance in blocking external water and oxygen, and the packaging structure of the OLED panel has a great influence on the light emitting efficiency of the OLED panel.